Field
Embodiments of the present disclosure generally relate to capacitive sensors having improved response symmetry.
Description of the Related Art
Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location, and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems, such as touchpads integrated in, or peripheral to, notebook or desktop computers. Proximity sensor devices are also often used in smaller computing systems, such as touch screens integrated in cellular phones or tablet computers.
Conventional mutual capacitance proximity sensors typically include two kinds of electrodes—referred to as transmitter electrodes and receiver electrodes—running orthogonal to each other to form a matrix of unique transmitter-receiver intersections. Each electrode is electrically connected at two edges of the sensor area, necessitating a border width in which conductive routing traces are disposed.
The requirement of a border width in conventional proximity sensors prevents the active area of the proximity sensor and, in some cases, the viewable portion of the display device from extending to the edge of the input device. Additionally, signals transmitted through the conductive routing traces may couple to nearby sensor electrodes, creating an asymmetrical response at transmitter-receiver intersections that are located near the border width of the input device.
Therefore, there is a need for improved electrodes configurations for mutual capacitance proximity sensors.